Improving the performance of BDS single-frequency precise point positioning by integrating QZSS observations in the Asia-Pacific region

Abstract

Japan’s Quasi-Zenith Satellite System (QZSS) as an important supplement to the Global Navigation Satellite System (GNSS) can provide great positioning, navigation and timing (PNT) services in the Asia-Pacific region. Many researches related to QZSS have focused on dual-/multi-frequency precise point positioning (PPP) or real-time kinematic (RTK) technology with high user costs. In this study, the contribution of QZSS to BDS-3/2 single-frequency (SF) PPP is investigated for the first time. Experimental results show that the three-dimensional (3D) positioning accuracy of the BDS-3-only and BDS-3 + 2 ionosphere-corrected (IC) SF-PPP through QZSS enhancement can be improved by 9.3% and 1.7% to 0.883 and 0.852 m, respectively. In the ionosphere-free (IF) SF-PPP, with the introduction of QZSS, the convergence time of the BDS-3-only or BDS-3 + 2 solutions can be improved by at least 21% and 8.2% in the horizontal and vertical directions, respectively. After convergence, the positioning accuracy of the BDS-3-only and BDS-3 + 2 IF SF-PPP can be improved by about 10% to 0.15 m in horizontal and 0.25 m in vertical. Compared to the IF SF-PPP, the convergence time of the ionosphere-weighted (IW) SF-PPP in the BDS-3-only and BDS-3 + 2 solutions can be improved by at least 57.6% to 13.5 min in horizontal and no more than 23% to 35.0 min in vertical. In this case of rapid convergence, it is hard to further optimize the convergence time of the BDS-3/2 IW SF-PPP by integrating the QZSS. Similar phenomena also appeared in the positioning accuracy of the IW SF-PPP. Nowadays, the 3D positioning accuracy of both IF and IW SF-PPP using BDS-3/2 + QZSS observations can reach 0.3 m in the Asia-Pacific region. Graphical abstract